Alkanedione dioximes



Patented Jan. 25, 1944 ,1, 1

Thur orr ce 2,340,271 ALKANEDIONE DIOXIME-S- Samuel B. Lippincott; TerraHaute, 1nd,, assignor. to' Commercial Solvents- Corporation, Terre Haute, 11111., a corporation of Maryland- No Drawing. Original application July 8,1940,v Serial No. 344,371 Divided andthisapplication April '25, .1941, Serial No. 390,335 r 4' Claims. (Cl. 260-556) invention relates to new and useful compositions of matter.

mula:

NOH H NOH Ink-t ts wherein R represents a low molecular alkyl-group;

These compounds are white crystalline substances which may be purified easily by=recrystallization from. methanol or other suitable solvents. As may be observed from the above structural formula, the compounds of myinvention have two reactive groups and, as a result, are useful as intermediates for the synthesis of numerous organic compounds. These" compounds are especially useful in the preparation of the corresponding isoxazoles, by either acid or alkaline hydrolysis thereof, as described in my U. S; Patent 2,260,256 of October 21, 1941.

Formation of the dioximes of my invention from nitroparaffins, is believed to proceed in accordance with the following equation, although the exact mechanismof the reaction is not known:

NOH 11 NOH The production of such dioximes may be effected by maintaining the reaction temperature at a level sufiiciently low to.prevent substantial hydrolysis of the dioximes to the corresponding isoxazoles. Since I have found that the presence of strong alkalies tends to' favor formation of isoxa'zoles even when employing relatively low temperatures I prefer to utilize weaker alkaline condensation agents such as, for example, ammoniabases, The term-ammonia base as used herein is intended to be construed as signifying ammonia and compounds in which one or'more hydrogen atoms of ammonia may be substituted by neutral or basic aliphatic groups. Alkyl amines such as ethyl amine, diethyl amine, triethyl amine, propyl amines, butyl amines, and the like, are very satisfactory for this purpose. It is to be understood, however, that the alkyl amines are merely preferred alkaline condensation agents, and that other bases of equivalent alkalinity may be employed with similar success. The amount of alkaline condensation agent to be employed may vary within relatively wide limits. There is reason to believe that the mechanism of this reaction involves the neutralization of one More particularly, it relates to. dioximes having the following structural for-- mole of nitric acidlpenmoleof dioxime formed.v For this reasonit is desirable to employ at least one-third equivalent of alkalinematerial penmole of 'nitroparaffins. An excess of arelatively weakl base is not detrimental and, in general, I prefer "to' employ at least onemole of an alkyl'amine,

or equivalent, alkaline converting agent per mole of nitroparaffin.

.The. production a of the dioximes .is preferably effected in a solvent medium which-is a common solventfor. thenitroparafiinsand alkali, or the resulting.nitroparaffinsalt; and. in which the dioxime isrelatiVely insoluble; Water constitutes al very, satisfactory solvent medium, especially, for the production of. dioximes from the lower nitroparaflins. It ,-is .obvious, however, that other.

solvents havingthe above characteristics rmayrbe. used in place of water. The. amount of solvent to be employed is not critical. For instance; I

have'. effected the reaction in the absence,of,anysolvent and in. the presence of water in amounts varying. from mole of water per mole offi'nitroparafiin to 50. moles of waterv per mole of ni. troparaffin, obtaining dioximes in all cases. I prefer, however, toemploy from 0.25'to, 5.0 moles of' water per mole of nitroparafli'n inmost in.- stances.

The production ofithedioximes-should beef-- fected at relatively, low temperatures, i. e., be-- low'50" C. and preferably at temperatures of.'10'? C. to +30"v C. Iiow temperatures. tendto preventv the hydrolysis of the dioxime, especially in the case of the lower molecular weight nitroparafiins. When reacting low molecular weight nitroparafiins and especially nitroethane, I prefer to employ temperaturesbelow ordinary room temperatures.- The reaction, temperature should bemaintained sufficiently low to prevent theformation of hydrolytic products, i. e., isoxazoles, butsufficiently high to secure a reasonable-ream tion rate of formation of the crystalline dioximes. Obviously, however, unduly low temperatures result in reaction rates so low as to be undesirable from a commercial point of view.

The reaction may be effected simply by mixing the nitroparaflins and alkaline converting agents with or without a solvent, and allowing the mixture to stand at reaction temperature until the reaction is complete as evidenced by the discontinuation of the formation Of a crystalline precipitate. The reaction can, however, be initiated at a somewhat higher temperature than'the desired reaction temperature and then cooled to reaction temperature for the completion of the reaction. Thus, I have allowed reaction mixtures of this type to stand atroom temperature for an initial period and then completed the reaction at approximately C.

Any of the primary nitroparafiins which contain more than one carbon atom may be transformed into dioximes by my process.

The following examples to which, however, the present invention is not limited, are illustrative:

Example I Nitroethane, diethyl amine, and water were the alkaline condensation agent, and the twoproducts were found to be identical by determining the melting point of a mixture of the products.

Example II A mixture of l-nitropropane, n-propylamine, and water, in a ratio of one mole of nitropropane, one mole of n-propylamine, and one-fourth mole of water, was prepared and allowed to stand at room temperature. Crystallization ensued without seeding, and at the conclusion of crystal growth, the mixture. was cooled to 0 C. and filtered. The resultant crystalline product was washed with water and the wash water added to the mother. liquor, theresulting mixture being cooled to 0 C. to secure a second crop of crystals. The product, 4-ethyl-3,5-heptanedione dioxime, was obtained in a yield of 58% of the theoretical amount. After purification by recrystallization from methanol, the product was found to have a melting pointrofv 135.4 C. This compound was also prepared by the use of ammonia, n-butylamine, and 2-aminoheptane, as the alkaline condensation agent, and, in eachcase, was found by the determination of a mixed melting point to be identical with the above product. The above compound was analyzed and found to have a nitrogen content of 15.19% as compared to 15.05% for theory.

Example III A mixture of l-nitrobutane, n-butylamine, and water, in the proportions of one mole of l-nitrobutane, one mole of n-butylamine, and one-fourth mole of water, was allowed to stand at room temperature. Crystal formation occurred without seeding and, at the conclusion thereof, the mixwere separated by filtration ture was cooled to 0 C. and allowed to stand at this temperature until no additional crystal growth could be observed. The product was recovered by means 01' filtration and the mother liquor was again cooled to 0 C. to obtain a second crop of crystals. The product, 5-propyl-4,6- nonanedione dioxime, was obtained in a yield of 37% of the theoretical amount. After recrystallization from methanol, this compound was found point of 116.4-116.8 C. and (theoretical to have a melting a nitrogen content of 12.19% 12.27%).

It is to be understood, of course, that the above examples are merely illustrative and do not limit hescope of my invention in any manner. On the contrary, the present invention is generally applicable to the production of dioximes from any of the primary nitroparafiins (l-nitroalkanes) containing more than one carbon atom. As has previously been pointed out, other alkaline condensation agents might be employed in place of the specific amines employed in the examples, and the reaction conditions utilized in the examples can be varied in numerous respects with substantially the same results. In general, it may be said that the use of any equivalents or modifications of Procedure which would naturally occur to those skilled in the art, is included within the scope of my invention.

This is a division of my co-pending application, U. S. Serial No. 344,371, filed July 8, 1940.

My invention now having been described, what I claim is;

1. A dioxime having the formula:

NOH H NOH CH3( C -CH3 (3H3 2. A dioxime having the formula:

methanol.

SAMUEL B. LIPPINCOTT.

CERTIFICATE OF CORRECTION. Patent No. 2,5L 0,271. January 2 19M.

SAMUEL B. LIPPINCOTT.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 1, first column, line 29, for that portion of theformula reading "HNO read HNO and that the said Letters Patent shouldbe read with this correction there'- in that the same may conform to therecord of the case in the Patent Office.

Signed and sealed this 25rd day: oi May, A. D. 191m.

Leslie Frazer (Seal) & Acting Commissioner of Patents. 

